WINNIPEG, Manitoba (Reuters) - More than 10,000 Canadian cattle remained confined on Friday to farms that received suspect feed last month, although Canada's chief veterinarian said it was extremely unlikely the feed could cause mad cow disease.

The cattle are on 113 farms in Ontario and Quebec that received feed with an ingredient that may have contained trace amounts of meat and bone meal made from cattle.

Since 1997, Canada has banned meat and bone meal from feed for cattle and other ruminant livestock because of the risk of spreading bovine spongiform encephalopathy, or mad cow disease.

Canada's detailed investigation into the feed ban infraction is now being reviewed by scientific experts in Europe and Asia, said Brian Evans, chief veterinarian at the Canadian Food Inspection Agency.

"The potential that these animals could develop BSE over time is remote. One cannot say zero, and that's the reason by which precautionary measures have been taken," Evans said in an interview.

Canada has had eight cases of mad cow disease in its domestic herd since May 2003, and hopes to eliminate the disease within a decade by tightening its feed rules.

Humans can develop a rare form of the fatal disease from eating contaminated meat, and 200 people have died from it, mainly in Britain, which experienced an outbreak of BSE in the 1980s.

Last month, Cargill Ltd. notified the CFIA that it had shipped a feed ingredient in a rail car that had not been completely cleaned out after previously containing meat and bone meal.

"The material of meat and bone meal that might have been present there was measurable in a matter of pounds: it wasn't a significant level of contamination," Evans said.

The CFIA's investigation found the meat and bone meal came from a slaughter plant that handled only young, healthy cattle unlikely to have developed mad cow disease, which takes an average of four to seven years to incubate.

The feed ingredient shipped in the rail car was added to the top of a feed mill's storage silo, and may not actually have been added to any feed rations before the mistake was uncovered, Evans said.

Cargill quickly recalled and destroyed the feed, he said.

About 80 percent of the livestock on the farms that received the feed were dairy cattle, and about 70 percent of the livestock were older animals, which are less susceptible to BSE, Evans said.

All the livestock have been permanently identified using Canada's national tracing system so that the CFIA can track them over their life spans, he said.

The livestock can be slaughtered and consumed in Canada, where food safety rules ban all brains, spines and other material that can harbor mad cow disease.

The meat might not be eligible for export, Evans said, depending on the technical requirements of importers.

In the short term, farmers are not allowed to otherwise sell or move the animals from their farms, Evans said.

"We're now starting to look at what are the other options that can be applied in segregating animals based on potential risk," he said.

Farmers have been patient, although they have some concern that their livestock may have a "stigma" because of the investigation, he said.

A spokesman for Cargill said the company has informed farmer-customers that it will help them through the process.

"We will ensure that our customers are not unfairly harmed by this, economically or otherwise," Rob Meijer said.

Cargill's suppliers have voluntarily started to use dedicated rail cars for shipping feed ingredients, he said.